High rate performance of lithium manganese nitride and oxynitride as negative electrodes in lithium batteries

A Comprehensive Review of Li-Ion Battery Materials and Their Recycling Techniques

In the context of constant growth in the utilization of the Li-ion batteries, there was a great surge in the quest for electrode materials and predominant usage that lead to the retiring of Li-ion batteries. This review focuses on the recent advances in the anode and cathode materials for the next-generation Li-ion batteries. To achieve higher power and energy demands of Li-ion batteries in future energy storage applications, the selection of the electrode materials plays a crucial role. The electrode materials, such as carbon-based, semiconductor/metal, metal oxides/nitrides/phosphides/sulfides, determine appreciable properties of Li-ion batteries such as greater specific surface area, a minimal distance of diffusion, and higher conductivity. Various classifications of the anode materials such as the intercalation/de- intercalation, alloy/de-alloy, and various conversion materials are illustrated lucidly. Further, the cathode materials, such as nickel-rich LiNixCoyMnzO2 (NCM), were discussed. NCM members such as NCM 333, NCM 523 that enabled to advance for NCM622 and NCM81are reported. The nanostructured materials bridged the gap in the realization of next-generation Li-ion batteries. Li-ion batteries’ electrode nanostructure synthesis, performance, and reaction mechanisms were considered with great concern. The serious effects of Li-ion batteries disposal need to be cut significantly to reduce the detrimental effect on the environment. Hence, the recycling of spent Li-ion batteries has gained much attention in recent years. Various recycling techniques and their effect on the electroactive materials are illustrated. The key areas covered in this review are anode and cathode materials and recent advances along with their recycling techniques. In light of crucial points covered in this review, it constitutes a suitable reference for engineers, researchers, and designers in energy storage applications.

Percolation behaviors of ionic and electronic transfers in Li3-2xCoxN

Nitridocobaltates Li3-2xCoxN, with Li3N-type layered structure, are promising compounds as negative electrode materials for Li-ion batteries. In the present paper, we report the first detailed broadband dielectric spectroscopy (BDS) study on lithiated transition metal nitrides. The ionic and electronic conductivities of Li3-2xCox□xN compounds (0 ≤ x ≤ 0.44) are investigated as a function of the concentration x of cobalt ions, cationic vacancies (□) and lithium ions. Dielectric and conductivity spectra were recorded within the frequency range of 60-1010 Hz from 200 to 300 K. Experimental results exhibit two types of electric conduction: the first one is due to lithium ion diffusion (for 0 ≤ x ≤ 0.25) and the second one due to electronic transfers (for x ≥ 0.3). Furthermore, two percolation transitions are evidenced and associated with 3D ionic transfers (threshold at x ≈ 0.11) on the one hand and 2D electronic transfers (threshold at x ≈ 0.30) on the other hand. Upon increasing the frequency, dielectric relaxations appear from larger to smaller sample scales. These successive polarizations appear with increasing frequency in the following order: (a) sample/silver paint interface; (b) particles (aggregates of grains); (c) grains (crystallites); (d) local ionic and electronic motions within the grains. Evolutions of dielectric relaxation parameters (dielectric strength and relaxation frequency) with Co content confirm the two percolation transitions. Surprisingly, the grain conductivity has a large discontinuity immediately below the electronic percolation threshold where any local- and long-range ionic movement disappears without electronic transfer. This discontinuity would be due to a narrow transition from ionic to electronic conduction when x increases.

On the viability of Mg extraction in MgMoN2: a combined experimental and theoretical approach

Layered MgMoN₂ was prepared by solid state reaction at high temperature between Mo and Mg₃N₂ in N₂ which represents a simple synthetic pathway compared to the previously reported method that used NaN₃ as the nitrogen source. The crystal structure of MgMoN₂ was studied by synchrotron X-ray and neutron powder diffraction. The feasibility of oxidizing this compound and concomitantly extracting magnesium from the structure was assessed by both chemical and electrochemical approaches, using different protocols. The X-ray diffraction patterns of the oxidized samples do not exhibit any relevant difference with respect to that of the as prepared MgMoN₂ and no differences in the cell parameters are deduced from Rietveld refinements. No hints pointing at the presence of any amorphous phase are observed either. These results are rationalized through DFT calculated energy barriers for Mg²⁺ ion migration in MgMoN₂.

Unravelling redox processes of Li7MnN4 upon electrochemical Li extraction–insertion using operando XAS

Evolution upon electrochemical oxidation of the Li₇MnN₄ Mn K-edge absorption spectra has been described using 3 distinctive local environments.

First-principle investigation on growth patterns and properties of cobalt-doped lithium nanoclusters

A systematic theoretical investigation on cobalt lithium clusters LinCo [1-12] was performed with a DFT approach. The location of global minima and structural evolution were carried out using the partical swarm optimization method. Li6Co is the transition structure in going from low-coordinated structures to three-dimensional torispherical structures with a cobalt atom enclosed by lithium atoms. Maxima of ∆2 E and E b for LinCo were found at n = 3, 6, 8, 10, indicating that these clusters possess higher relative stability than their neighbors. In comparison with small clusters, n = 1-6, the greater electron transfer from Li-2s to Co-3d within cage-like clusters LinCo (n = 7-12) strengthens the bonding effect between Lin and Co, which is reflected in the Wiberg bond index of Co and atomic binding energy analysis. AdNDP analysis verified the presence of both Lewis bonding elements (1c-2e objects) and delocalized bonding elements (6c-2e, 9c-2e and 10c-2e bonds). It is hoped that this theoretical work will provide favorable information to help understand the influence of dopant transition metal atoms on the properties of lithium-based materials.

New synthesis route for ternary transition metal amides as well as ultrafast amide-hydride hydrogen storage materials

K2[Mn(NH2)4] and K2[Zn(NH2)4] were successfully synthesized via a mechanochemical method. The mixture of K2[Mn(NH2)4] and LiH showed excellent rehydrogenation properties. In fact, after dehydrogenation K2[Mn(NH2)4]-8LiH fully rehydrogenates within 60 seconds at ca. 230 °C and 5 MPa of H2. This is one of the fastest rehydrogenation rates in amide-hydride systems known to date. This work also shows a strategy for the synthesis of transition metal nitrides by decomposition of the mixtures of M[M'(NH2)n] (where M is an alkali or alkaline earth metal and M' is a transition metal) and metal hydrides.

Mesoporous coaxial titanium nitride-vanadium nitride fibers of core-shell structures for high-performance supercapacitors

In this study, titanium nitride-vanadium nitride fibers of core-shell structures were prepared by the coaxial electrospinning, and subsequently annealed in the ammonia for supercapacitor applications. These core-shell (TiN-VN) fibers incorporated mesoporous structure into high electronic conducting transition nitride hybrids, which combined higher specific capacitance of VN and better rate capability of TiN. These hybrids exhibited higher specific capacitance (2 mV s(-1), 247.5 F g(-1)) and better rate capability (50 mV s(-1), 160.8 F g(-1)), which promise a good candidate for high-performance supercapacitors. It was also revealed by electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) characterization that the minor capacitance fade originated from the surface oxidation of VN and TiN.